Thinking about what happened in Baltimore and wondered if huge ships have a way to rapidly deploy anchors if the ship becomes uncontrollable close to shore. Independent of engine power.
In: Engineering
Anchors don’t work in real life like they do in movies. In movies anchors act like grappling hooks, they catch on something on the sea floor and immediately the chain pulls tight and the ship stops (Battleship). In reality an anchor is just the end bit that gives a little bit of bite or resistance to allow the chain to pull out and lie in the sea floor. Hundreds of feet of really heavy chain lying on the sea floor provides a steady point for the ship to hold on to to try and stay still…ish. If the ship starts moving too much it can gain enough momentum to drag the anchor and chain, slowing the ship down but not keeping it in place.
In the case of the Baltimore ship, it was probably redirected by some fluid dynamic forces due to an intersection of channels (kind of like lane keep assist does when coming up on an exit or lane split without a dashed line). This wouldn’t have been an issue under power, but just free floating it was.
After loosing power it was going too fast for its anchors to stop it before it hit the bridge. The best case would be to use the anchors to try and steer the ship, which they did, but turning a 100,000 ton skyscraper lying on its side and moving at 8mph is going to take a lot of chain and time to make a difference, they just didn’t have that.
To put it into perspective, the ship had 1.17B Newtons of force behind it. A typical 70mph car crash might be closer to 200,000N of force.
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